Effects of hyperbaric oxygen on cochlear impairment due to noise in the guinea pig
Luo, L.
Zhonghua Yu Fang Yi Xue Za Zhi 22(4): 241-243
1988
ISSN/ISBN: 0253-9624 PMID: 3219965 Document Number: 319642
In this experiment we allowed one group of guinea pigs to immediately breathe in hyperbaric oxygen (OHP) for 85 minutes (2 ata) after continuously exposure to 110 dB SPL white noise for 6 hours a day for 20 days, and compared with another group with similar exposure which breathe in OHP (2 ata) for 85 minutes every day for 10 days after a 14-day interval. The cochlear microphonic (CM) and the histopathological changes of the cochlea were then examined. The results showed: 1. The average threshold shift of produced 20.mu.V CM at each frequency in the tested frequencies of 250, 500, 1000, 2000, 4000 Hz was significantly lower in the guinea pigs immediately breathing in OHP after exposure to noise than in those only exposed to noise. The degree of the cochlear histopathological impairment was also lighter than in those only exposed to noise. 2. In the guinea pigs breathing in OHP after a 14-day interval, the average threshold shift of CM was significantly lower than in those only exposed to noise at the tested frequencies of 250, 500, 1000 Hz. The degree of the cochlear histopathological impairment was less severe than in those only exposed to noise but slightly more severe than in those immediately breathing in OHP after exposed to noise. Breathing in OHP probably increases the blood flow and the oxygen content in endolymph and perilymph as well as in blood, improves the condition of ischemia and anoxia due to noise, increases the oxidative metabolism, then reduces the injurious effects caused by noise in the cochlea and promotes its recovery.